HM Revenue & Customs have sent warning letters to Letting Agents demanding they provide landlord rental income records. They make such demands under paragraph 18 of Schedule 23 to the Finance Act 2011.
Under that section of the Finance Act, HMRC can force letting agents to provide for every customer:
Gross Rents collected
Name and address of the landlord
The addresses of each let property
The Landlord Crackdown on Tax has been well announced and HMRC is now using data held by suppliers of landlords to target the offenders.
Double check your returns and review them with your accountant.
